选择合适的单词或短语并用其正确形式填空
depend on cheer up get the hang pf
1.We must try to ______ the new telephone system before we use it so that we may use it freely.
2.He was unhappy at first but soon ____ after lunch.
3.The sun is very important to the mankind.Man ____ it for heat and light.
请翻译句子,